<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8" />
  <meta http-equiv="X-UA-Compatible" content="IE=edge" />
  <meta name="viewport" content="width=device-width, initial-scale=1.0" />
  <title>25.多级菜单的弹性布局</title>
  <style>
    * {
      padding: 0;
      margin: 0;
    }

    body {
      height: 100vh;
      display: flex;
      flex-direction: column;
    }

    main {
      flex: 1;
      background: #f3f3f3;
    }

    footer {
      height: 50px;
      background: #ddd;
      display: flex;
      flex-direction: row;
      justify-content: space-between;
      border-top: solid 1px #ccc;
    }

    footer section {
      flex: 1;
      /* background: red; */
      border-right: solid 1px #ccc;
      display: flex;
      flex-direction: column-reverse;
    }

    footer section:last-child {
      border-right: none;
    }

    footer section h4 {
      flex: 0 0 50px;
      display: flex;
      flex-direction: column;
      justify-content: center;
      text-align: center;
      cursor: pointer;
    }

    footer section ul {
      display: flex;
      flex-direction: column;
      border: solid 1px #ccc;
      text-align: center;
      margin-bottom: 5px;
      border-radius: 10px;
      margin: 5px
    }

    footer section li {
      flex: 1 0 50px;
      display: flex;
      flex-direction: column;
      justify-content: center;
      border-bottom: solid 1px #ccc;
      cursor: pointer;
      ;
    }

    footer section li:last-child {
      border-bottom: none;
    }
  </style>
</head>

<body>
  <main></main>
  <footer>
    <section>
      <h4>教程</h4>
      <ul>
        <li>PHP</li>
        <li>CSS</li>
      </ul>
    </section>
    <section>
      <h4>直播</h4>
    </section>
    <section>
      <h4>软件</h4>
    </section>
  </footer>
</body>

</html>